Merge branches 'omap1-upstream' and 'omap2-upstream' into devel
[linux-2.6] / arch / powerpc / platforms / cell / cbe_cpufreq.c
1 /*
2  * cpufreq driver for the cell processor
3  *
4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
5  *
6  * Author: Christian Krafft <krafft@de.ibm.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2, or (at your option)
11  * any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22
23 #include <linux/cpufreq.h>
24 #include <asm/machdep.h>
25 #include <asm/of_platform.h>
26 #include <asm/prom.h>
27 #include <asm/cell-regs.h>
28 #include "cbe_cpufreq.h"
29
30 static DEFINE_MUTEX(cbe_switch_mutex);
31
32
33 /* the CBE supports an 8 step frequency scaling */
34 static struct cpufreq_frequency_table cbe_freqs[] = {
35         {1,     0},
36         {2,     0},
37         {3,     0},
38         {4,     0},
39         {5,     0},
40         {6,     0},
41         {8,     0},
42         {10,    0},
43         {0,     CPUFREQ_TABLE_END},
44 };
45
46 /*
47  * hardware specific functions
48  */
49
50 static int set_pmode(unsigned int cpu, unsigned int slow_mode)
51 {
52         int rc;
53
54         if (cbe_cpufreq_has_pmi)
55                 rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
56         else
57                 rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
58
59         pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
60
61         return rc;
62 }
63
64 /*
65  * cpufreq functions
66  */
67
68 static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
69 {
70         const u32 *max_freqp;
71         u32 max_freq;
72         int i, cur_pmode;
73         struct device_node *cpu;
74
75         cpu = of_get_cpu_node(policy->cpu, NULL);
76
77         if (!cpu)
78                 return -ENODEV;
79
80         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
81
82         /*
83          * Let's check we can actually get to the CELL regs
84          */
85         if (!cbe_get_cpu_pmd_regs(policy->cpu) ||
86             !cbe_get_cpu_mic_tm_regs(policy->cpu)) {
87                 pr_info("invalid CBE regs pointers for cpufreq\n");
88                 return -EINVAL;
89         }
90
91         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
92
93         of_node_put(cpu);
94
95         if (!max_freqp)
96                 return -EINVAL;
97
98         /* we need the freq in kHz */
99         max_freq = *max_freqp / 1000;
100
101         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
102         pr_debug("initializing frequency table\n");
103
104         /* initialize frequency table */
105         for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
106                 cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
107                 pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
108         }
109
110         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
111
112         /* if DEBUG is enabled set_pmode() measures the latency
113          * of a transition */
114         policy->cpuinfo.transition_latency = 25000;
115
116         cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
117         pr_debug("current pmode is at %d\n",cur_pmode);
118
119         policy->cur = cbe_freqs[cur_pmode].frequency;
120
121 #ifdef CONFIG_SMP
122         policy->cpus = cpu_sibling_map[policy->cpu];
123 #endif
124
125         cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
126
127         /* this ensures that policy->cpuinfo_min
128          * and policy->cpuinfo_max are set correctly */
129         return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
130 }
131
132 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
133 {
134         cpufreq_frequency_table_put_attr(policy->cpu);
135         return 0;
136 }
137
138 static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
139 {
140         return cpufreq_frequency_table_verify(policy, cbe_freqs);
141 }
142
143 static int cbe_cpufreq_target(struct cpufreq_policy *policy,
144                               unsigned int target_freq,
145                               unsigned int relation)
146 {
147         int rc;
148         struct cpufreq_freqs freqs;
149         unsigned int cbe_pmode_new;
150
151         cpufreq_frequency_table_target(policy,
152                                        cbe_freqs,
153                                        target_freq,
154                                        relation,
155                                        &cbe_pmode_new);
156
157         freqs.old = policy->cur;
158         freqs.new = cbe_freqs[cbe_pmode_new].frequency;
159         freqs.cpu = policy->cpu;
160
161         mutex_lock(&cbe_switch_mutex);
162         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
163
164         pr_debug("setting frequency for cpu %d to %d kHz, " \
165                  "1/%d of max frequency\n",
166                  policy->cpu,
167                  cbe_freqs[cbe_pmode_new].frequency,
168                  cbe_freqs[cbe_pmode_new].index);
169
170         rc = set_pmode(policy->cpu, cbe_pmode_new);
171
172         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
173         mutex_unlock(&cbe_switch_mutex);
174
175         return rc;
176 }
177
178 static struct cpufreq_driver cbe_cpufreq_driver = {
179         .verify         = cbe_cpufreq_verify,
180         .target         = cbe_cpufreq_target,
181         .init           = cbe_cpufreq_cpu_init,
182         .exit           = cbe_cpufreq_cpu_exit,
183         .name           = "cbe-cpufreq",
184         .owner          = THIS_MODULE,
185         .flags          = CPUFREQ_CONST_LOOPS,
186 };
187
188 /*
189  * module init and destoy
190  */
191
192 static int __init cbe_cpufreq_init(void)
193 {
194         if (!machine_is(cell))
195                 return -ENODEV;
196
197         return cpufreq_register_driver(&cbe_cpufreq_driver);
198 }
199
200 static void __exit cbe_cpufreq_exit(void)
201 {
202         cpufreq_unregister_driver(&cbe_cpufreq_driver);
203 }
204
205 module_init(cbe_cpufreq_init);
206 module_exit(cbe_cpufreq_exit);
207
208 MODULE_LICENSE("GPL");
209 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");